Various types of machines have been proposed for converting a shallow cup into a drawn and ironed container. These machines usually consist of a punch or ram which is reciprocated along a path on a frame with a plurality of ironing dies arranged along the path. Usually the plurality of ironing dies are assembled into a package that is commonly referred to as a "tool pack" and having a lubricating ring interposed between each pair of adjacent ironing dies.
A cup locator is usually positioned at the entry end to the tool pack and the cups are either gravity-fed or positively-fed to the locator where they are picked up by the moving punch and are moved through the ironing dies to reduce the thickness of the side wall of the shallow cup and increase the height thereof.
U.S. Pat. No. 3,735,629 discloses one type of drawing and ironing machine or apparatus, which consists of a redraw assembly, three ironing assemblies and a stripper assembly, all arranged along the path for a punch so that a cup can be placed on the end of the punch and then forced through the respective assemblies to decrease the wall thickness and increase the height. At the end of the stroke for the punch, a domer assembly cooperates with the end of the punch to reform the end wall and the finished container is removed from the punch by the stripper assembly while the punch is returned to its original position.
For effective and prolonged operating life, it is essential that proper alignment of the ironing dies and the ram be established and maintained at all times. Various proposals have been suggested for mounting the ironing dies, and one such type is disclosed in U.S. Pat. No. 4,300,375. In this patent, the tool pack consists of three separate modules, with each module including at least one ironing die, as well as other components, such as a lubricating ring and guide rings. In assembly of the tool pack disclosed in this patent, the first module containing the first ironing die is positioned into an opening in the frame of the tool pack while the third ironing module (that has the third ironing ring) is positioned into an opening at the opposite end and the second module with the second ironing ring is then inserted between the two.
While this arrangement has been very satisfactory in maintaining accurate alignment of the ironing rings with respect to the path of the movable punch, certain deficiencies have been noted with respect to this assembly. For example, it is well known that the first ironing ring is subjected to the most wear and must be replaced more frequently than the second and third ironing assemblies. In the tool pack disclosed in the above patent, the second ironing module must first be removed before the first module can be removed, in order to replace the first ironing ring, the entire assembly must be separated by removal of several bolts.
In view of the need for special tools and the like, replacement of an ironing die is accomplished in the tool shop, rather than at the site of the machine. Thus, this requires considerable down-time for the machine in order to replace a single ironing die. Furthermore, the respective modules are rather heavy, weighing on the order of about 60 lbs., and are difficult to manipulate in a very confined space.
Thus, there remains a need for a tool pack assembly that can maintain accurate alignment and at the same time incorporate features that allow rapid replacement of an ironing die without disturbing the remainder of the assembly.